The Business Model Canvas, developed by Alexander Osterwalder, is a one-page framework with nine building blocks -- including customer segments, value propositions, channels, revenue streams, and cost structure -- that lets a founder sketch and test an entire business model before writing a lengthy plan. A value proposition statement answers one question clearly: why should this specific customer choose your product over doing nothing or choosing a competitor -- effective ones name the customer, the problem, and the specific benefit, without vague buzzwords. Revenue streams describe how the business actually earns money: options include one-time sales, subscriptions, commissions, advertising, or licensing, and many businesses combine more than one. Testing the model on paper -- questioning each block before spending money -- catches weak assumptions (such as a channel that doesn't reach your real customers) far earlier than building the product first.